1. Field of the Invention
The present invention relates to a shearing machine which is provided with upper and lower shearing blades and can be used to cut or shear a sheet-like workpiece such as a sheet metal into many finished sheets which are referred to as blanks.
2. Description Of the Prior Art
As is well-known, a shearing machine is provided with a pair of upper and lower shearing blades and is used to cut or shear a work-sheet or sheet-like workpiece such as a sheet metal into many finished sheets which are referred to as blanks. Each of the upper and lower shearing blades is designed to be straightly elongated in many cases but is also designed to be L-shaped to shear the work-sheet into L-shaped configurations. The shearing machine is also provided with a hold-down means for holding the work-sheet to be sheared and a work-table on which the work-sheet to be sheared is moved to be fed into and positioned between the upper and lower shearing blades. Furthermore, the shearing machine is often provided with a workpiece clamping and positioning means for clamping and positioning the work-sheet on the work-table between the upper and lower shearing blades. The work-sheet clamping and positioning means comprises a first carriage means movable toward and away from the upper and lower shearing blades and a second carriage means which has a clamping means for clamping the work-sheet and is movable on the first carriage means at right angles with the travelling course thereof. After a work-sheet has been sheared into as many blanks as possible in such a shearing machine, the end portion of the work-sheet which is clamped by the clamping means cannot be utilized as blanks and is disposed of as a scrap.
In the shearing machine of the above described arrangement, it is necessary to keep the upper shearing blade in parallel with the travelling course of the second carriage of the work-sheet clamping and positioning means so as to perform accurate shearing operations. Heretofore, however, it has been very difficult and time-consuming to adjust the parallelism of the upper shearing blade, since it has been necessary to adjust the mounting of the work-sheet clamping and positioning means or the upper shearing blade in its entirely.
It has been another disadvantage with conventional shearing machines that tremendous noises will occur each time when the work-sheet to be sheared is held down by the hold-down means.
Also, it has been customary that scraps produced from work-sheets during shearing operations are handled in the same manner as blanks and are mingled into blanks. Accordingly, it has been necessary in conventional shearing machines to pick up or select out scraps from blanks after work-sheets have been sheared in shearing operations.
There have been some shearing machines which are provided with a scrap removing means for removing a scrap each time when a work-sheet has been sheared into blanks. However, in conventional shearing machines, such a scrap removing means is so arranged as to remove scraps at a position where work-sheets are to be fed to be sheared. Accordingly, it has been conventionally disadvantageous even in that work-sheets cannot be fed to be sheared when scraps are being removed with a result that plenty of idle time is necessary, even if a scrap removing means is provided.